US 8052629 B2
A multi-fit orthotic structure including an attachment system for coupling the orthotic structure to a wide variety of subjects without requiring a custom fit. In one embodiment, active mobility assistance is provided via an orthotic system capable of integrating a linear actuator and linkage system to deliver torque to the lower leg of a subject to facilitate flexion and/or extension motion of the subject's leg. The orthotic structure is attached to the subject using a textile suspension system which does not require the orthotic structure to interface directly in the knee region or at the lateral areas of the thigh and calf of the subject, thus providing an ideal fit for the widest possible range of subjects with the minimum number of required sizes.
1. A multi-fit orthotic apparatus using a textile-based suspension, the apparatus comprising:
a thigh orthotic structure coupled with a thigh suspension textile;
a lower leg orthotic structure coupled with an upper shin suspension textile;
a lateral support structure coupled with a lower leg suspension textile, the lateral support structure positioned on both lateral sides of a lower leg of a subject, wherein each suspension textile conforms closely to the subject to accommodate a wide range of subjects without a custom fit;
a tibia anterior structure;
a tibia posterior structure coupled with the tibia anterior structure; and
a tibia suspension system coupled with the tibia posterior structure and the lateral support structure to transmit force to the lateral support structure.
2. The multi-fit orthotic apparatus of
an independent proximal thigh textile tensioning system coupled with the thigh suspension textile, the proximal thigh textile tensioning system configured to adjust tension across a thigh of the subject and to distribute force evenly throughout the thigh suspension textile to gain leverage when applying torque to a leg of the subject;
an independent knee-lock textile tensioning system coupled with the upper shin suspension textile, the knee-lock textile tensioning system configured to adjust tension around a knee region of the subject; and
an independent lower shin textile tensioning system coupled with the lower leg suspension textile, the lower shin textile tensioning system configured to adjust tension across the lateral support structure.
3. The multi-fit orthotic apparatus of
The present patent application claims priority to and incorporates by reference the corresponding provisional patent application Ser. No. 61/027,365, entitled, “Multi-Fit Orthotic and Mobility Assistance Apparatus” filed on Feb. 8, 2008.
At least certain embodiments of the invention relate generally to functional rehabilitation and mobility enhancement of patients who have suffered loss of function due to injury, disease or other condition, and more particularly, but not exclusively, to orthotic devices for functional rehabilitation.
Devices to assist individuals with impaired mobility due to illness or injury include passive and active assistance and support devices, mobility devices and strength training devices. Passive assistance and support devices, such as canes, crutches, walkers and manual wheelchairs, provide assistance with mobility. However, individuals using such devices must supply all of the power needed by exerting forces with other muscles to compensate for the muscle that is weak or injured. Additionally, many passive assistance and support devices provide limited mobility.
Many types of existing passive knee braces are available for stabilizing the knee to prevent or recover from injury, or to provide stability for chronic conditions. Existing braces typically come in either a few standard sizes or are custom-fitted to each patient. The standard sizes often cannot conform closely to the unique shape of an individual leg and may suffer from poor fit. The custom-fitted braces are expensive and cannot be re-used by other patients after the brace is no longer needed. Both types of brace typically rely on the tightness of fit to keep them from sliding down the leg. Keeping these braces in the proper position is a largely unmet problem.
Existing orthotic designs have many points of structural contact with the subject's body. Each contact point must be custom molded to a specific shape to meet the wide array of dimensions and geometries of subjects. Otherwise, the points of contact will be sub-optimal and will result in discomfort and pain. Additionally, existing knee braces have not been designed to couple with actuators to provide active assistance. Most passive braces do not have the required structure or attachment points to allow an actuator to be coupled.
Moreover, existing devices such as continuous passive motion (CPM) machines and robotic therapy devices involve the use of an external force to flex and extend a subject's limb to induce motion. Continuous passive motion of a joint following injury, illness or surgery has been found to reduce the post-operative pain, decrease adhesions, decrease muscle atrophy, and enhance the speed of recovery, while minimizing various risks of mobilization. CPM machines slowly and gently move a subject's leg through a reciprocal cycle between a flexion position in which an angle between the subject's femur and tibia is at a minimum, and an extension in position in which the angle between the subject's femur and the tibia is at a maximum. However, CPM machines are not sufficiently small and light as to allow attachment directly to a subject's leg (or other body part) and do not allow for mobility, typically requiring the subject to be in the reclined or sitting position during operation.
At least certain embodiments of the invention disclose methods and apparatuses including a multi-fit orthotic structure with an attachment system for coupling the orthotic structure to a wide variety of subjects without requiring a custom fit. In one embodiment, active mobility assistance is provided via an orthotic system capable of integrating a linear actuator and linkage system to deliver torque to the lower leg of a subject to facilitate flexion and/or extension motion of the subject's leg. The orthotic structure is attached to the subject using a textile suspension system which does not require the orthotic structure to interface directly in the knee region or at the lateral areas of the thigh and calf of the subject, thus providing an ideal fit for the widest possible range of subjects with the minimum number of required sizes. The multi-fit orthotic structure also allows a single device to be worn on either the right or left leg. Additionally, a textile suspension system may be integrated into the attachment system to dynamically adapt to a wide range of subject's geometries.
A better understanding of at least certain embodiments of the invention can be obtained from the following detailed description in conjunction with the following drawings, in which:
Throughout the description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent to one skilled in the art, however, that the present invention may be practiced without some of these specific details. In other instances, well-known structures and devices are shown in block diagram form to avoid obscuring the underlying principles of embodiments of the invention.
Embodiments described herein include a relatively inexpensive orthotic system for functional rehabilitation of patients who have suffered loss of function due to illness or injury. The orthotic system is designed to conform closely to the unique shape of an individual subject's leg without requiring the expense of a custom fit, while being provided in the fewest possible sizes that accommodate the widest range of subjects. Additionally, the orthotic system described herein limits the points of structural contact of the primary orthotic structure to at most two (2) contacts: one on the proximal thigh and the other on the distal shin. This arrangement accommodates the shapes and sizes of a wide variety subject's appendages which occur between the two (2) contact points. By using a suspension textile with the ability to support, pad, and lock onto the subject, the structure is provided with the points of leverage and support required to constrain movement and assist as an exoskeleton. Embodiments are capable of attachment directly to the leg to provide not only support, but active mobility assistance in addition to continuous passive motion and robotic therapy. Embodiments also accommodate a center-mounted linear actuator and bell crank linkage coupled to the lower leg orthotic structure. Center mounting of the actuator along with the adjustability of the orthotic system allow the same device to fit either the right or left leg. A unified design eliminates the costs associated with the development, manufacturing and inventory, of different devices for each leg.
The bell crank 2 has one or more fixed pivots 103 on the same structure as the linear actuator 1 is mounted. In one embodiment, the bell crank 2 has dual fixed pivots 103, both in a coaxial configuration with respect to one another on opposite lateral sides of the orthotic system 100. The linear actuator 1 operates on a point at or near the midline of both the orthotic system 100 and the bell crank 2 to split the forces into two (2) nearly equal components to balance torque transferred to the lower structure. The bell crank 2 has two (2) output pivots 105 in the same lateral plane as the bell crank pivots 103; however, an alternate embodiment could have fewer or more output pivots 105 which are not necessarily aligned with the bell crank pivots 103. At least certain embodiments utilize two (2) link structures 7 which transfer forces to and from the lower orthotic structure 4. The thigh orthotic structure 3 is connected to the lower leg orthotic structure 4 using one or more hinge joints 8. In one embodiment, the hinge joints 8 are located on each lateral side of the orthotic system 100 such that they can be placed in a coaxial configuration relative to the joint of the subject wearing the orthotic system 100. The orthotic system 100 uses a geared polycentric hinge joint 8; however, alternate embodiments may include the use of single pivot joints as well as other linkage systems (such as a crossed four-bar linkage or other similar multi-axis joints). The link structures 7 act on individual pivots 107 on the lower leg structure 4; however, other embodiments include fewer or more pivots 107 or spherical joints.
In the illustrated embodiment, the distal portion of the tibia posterior structure 6 is affixed to the tibia suspension system 9 such that high levels of force may be transmitted to the top of the lateral support structures 10 positioned on each of the lateral sides of the lower leg of the subject. The lateral support structures 10 transmit forces vertically to the ankle suspension structure 11 and ultimately to the ground via the foot pad sensor system 12. The lateral support structures are attached to the lower leg textiles 13 which hold each of the lower leg components relative to one another and provide wide area support to the subject's body as well as padding between hard structures and the body. In one embodiment, the thigh textile 14 is attached to the thigh orthotic structure 3 at two (2) points at the proximal end of the structure as well as two (2) points laterally near each of the hinges 8. Alternate embodiments include the thigh textile 14 to be attached at one or more points at the distal end of the thigh orthotic structure 3 as well as one or more points at the proximal end of the thigh orthotic structure 3. In one embodiment, the upper shin textile 15 is affixed to the lower leg orthotic structure 4 at two (2) lateral points near each hinge. Other embodiments include affixing the upper shin textile 15 in fewer or more places.
The tibia suspension system 9 is embodied as an adjustable webbing strap which connects the distal end of the tibia posterior structure 6 and the proximal end of the lateral support structures 10. Alternate embodiments may include a combination of vertical force carrying tension structures which transfer force from any point on the tibia length system or similar anterior structure to any point on lateral structures similar to the lateral support structures 10. The foot pad sensor system 12 may be embodied by four (4) pressure sensitive sensors encased in textile. In at least certain embodiments, two sensors are located in the forefoot area and two are located under the heel of the subject. The design is such that the foot pad sensor can be reversed to accommodate both left and right feet. An optional toe strap 26 is similarly reversible left to right and allows the footpad to be secured to the foot to eliminate a tripping hazard as well as giving a point of attachment for anti-foot drop system 27.
The illustrated embodiment includes a passive foot drop tension system 27 which may be embodied as elastic webbing connecting the forefoot loop with the lower portion of the tibia posterior structure 6. Alternate embodiments may include active foot drop devices including linear and rotational actuators placed inline between the toe strap 26 and the distal portion of the tibia posterior structure 6 or which could be hydraulic, pneumatic, electric, or remotely actuated via cable. Alternate embodiments of the foot pad sensor system 12 include any number of sensors placed throughout the footpad. Additional embodiments of the pressure sensors in the orthotic design include placement of pressure sensors in anterior and posterior portions of the textiles as well as directly on the posterior side of the orthotic system facing the subject to facilitate determining the level of pressure and forces of exerted in and around these interfaces, and to automatically instruct or warn the subject of potential problems as well as facilitate using, for example, the pressure and force information as predictive feedback to software of the linear actuator for gait analysis.
The illustrated embodiment of
The illustrated embodiment of
Embodiments are not limited to the techniques and materials discussed herein. The structural elements could be constructed of carbon fiber, fiberglass, aluminum, steel or another rigid material. The textile portion could be comprised of any compliant material including fabric, webbing or flexible plastics. An embodiment has been described for the knee, but braces with the same the multi-fit and mobility-assistance features could be applied to other joints such as the ankle, elbow, hip and shoulder.
Throughout the foregoing specification, references to “one embodiment,” “an embodiment,” “an example embodiment,” indicate that the embodiment described may include a particular feature, structure, or characteristic; however every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. When a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to bring about such a feature, structure, or characteristic in connection with other embodiments, whether or not explicitly described. Various changes may be made in the structure and embodiments shown herein without departing from the principles of this description.
In the description as set forth above and claims, the terms “coupled” and “connected,” along with their derivatives, may be used. It should be understood that these terms are not intended to be synonymous with each other. Rather, in particular embodiments, “connected” is used to indicate that two (2) or more elements are in direct physical or electrical contact with each other. “Coupled” may mean that two (2) or more elements are in direct physical or electrical contact. However, “coupled” may also mean that two (2) or more elements are not in direct contact with each other, but yet still cooperate or interact with each other.
Embodiments of the invention may include various operations as set forth above or fewer operations or more operations, or operations in an order which is different from the order described herein. Throughout the foregoing description, for the purposes of explanation, numerous specific details were set forth in order to provide a thorough understanding of the invention. It will be apparent, however, to one skilled in the art that the invention may be practiced without some of these specific details. Accordingly, the scope and spirit of the invention should be judged in terms of the claims which follow as well as the legal equivalents thereof.